4/10 An unknown mass of aluminum requires 6290 joules to raise
the temperature from 23.9°C to 80.0°C. What is the mass of the
aluminum?
The specific heat of aluminum is 0.900 J/g.°C

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

the answer is c

tell me if wrong